Jim Mallinder admitted Saints were ‘chasing shadows’ in their Champions Cup thrashing at Castres on Saturday afternoon.
The French side scored five tries on their way to a 41-7 demolition of Mallinder’s men at Stade Pierre Antoine.
Saints could only reply through a late James Wilson score on a chastening afternoon for the club.
And Mallinder admitted his team were defeated in almost every area of the game.
“We were well beaten,” the Saints boss said.
“They were too physical for us and we didn’t get on the front foot at all during the first half.
“The little ball we got, we didn’t look after.
“We didn’t get enough numbers to the breakdown, tried some silly offloads that were never on and they punished us.”
Saints had beaten Montpellier 16-14 a week earlier thanks to a last-gasp Stephen Myler penalty.
But they were unable to produce the same kind of spirited display at Castres, who won easily.
“That’s the frustrating thing, that we’ve shown against big, physical packs - we can compete,” Mallinder said.
“But we just didn’t at all today.
“We were never on the front foot, we were chasing shadows basically.
“We got to half-time and it was really game over already.
“It’s a disappointing performance.
“You don’t want to come out to France and give them so much, and we did.
“Once a French team, particularly Castres, one of the best teams, get on the front foot, the sun is shining on their backs, the band starts playing, they’re a very difficult team to beat.”
Saints are in a transitional period, with attack coach Alex King having departed last week.
But Mallinder insists he can turn it around and has full confidence in his players, who must now pick themselves up for Friday’s Aviva Premiership game at home to Gloucester.
“We looked in the changing room and we’ve got some good, individual players, but at the moment we are not clicking and playing at our best,” he said.
“We have played some decent rugby this season, but there’s been too many performances like that, and that’s disappointing.
“We’ve just got to keep going with the players.
“We are changing things so we’re not just doing the same old things we’ve always done.
“We’ve got to get the confidence back in the players and we’ve got the players who can deliver - I’m certain of that.
“We saw we could deliver last week and we were hoping we could get some of our big international players back and that would make a difference.
“Courtney (Lawes) and Dylan (Hartley) were back and we were hoping that would give us a physical and mental edge, but unfortunately that didn’t happen.”